Ordiel Ordiel - 15 days ago 10
Java Question

Is it possible to create a NEW zip file using the java FileSystem?

I've successfully modified the contents of a (existing) zip file using the

FileSystem
provided by java 7, but when I tried to create a NEW zip file by this method it fails, with the error message that says:
"zip END header not found"
, it is logical because of the way I'm doing it, first I create the file (
Files.createFile
) which is a completely empty file, and then I try to access to its file system , and since the file is empty its impossible to find any header inside the zip, my question is is there any way to create a new zip file completely empty using this method?; the hack that I've considered is adding an empty new
ZipEntry
to a the zip file and then using that new empty file to crate the file system based on it, but i really want to think that the guys of oracle implemented a better (easier) way to do this with nio and the filesystems...

this is my code (the error appears when creating the file system):

if (!zipLocation.toFile().exists()) {
if (creatingFile) {
Files.createFile(zipLocation);
}else {
return false;
}
} else if (zipLocation.toFile().exists() && !replacing) {
return false;
}
final FileSystem fs = FileSystems.newFileSystem(zipLocation, null);
.
.
.


zipLocation
is a Path
creatingFile
is a boolean

ANSWER:
in my particular case the answer given didn't work appropriately because of the spaces in the path, therefore i have to do it the way i didn't want to:

Files.createFile(zipLocation);
ZipOutputStream out = new ZipOutputStream(
new FileOutputStream(zipLocation.toFile()));
out.putNextEntry(new ZipEntry(""));
out.closeEntry();
out.close();


it does not mean that the given answer is wrong, it just didn't work for my particular case

Answer

As described in The Oracle Site:

public static void createZip(Path zipLocation, Path toBeAdded, String internalPath) throws Throwable {
    Map<String, String> env = new HashMap<String, String>();
    // check if file exists
    env.put("create", String.valueOf(Files.notExists(zipLocation)));
    // use a Zip filesystem URI
    URI fileUri = zipLocation.toUri(); // here
    URI zipUri = new URI("jar:" + fileUri.getScheme(), fileUri.getPath(), null);
    System.out.println(zipUri);
    // URI uri = URI.create("jar:file:"+zipLocation); // here creates the
    // zip
    // try with resource
    try (FileSystem zipfs = FileSystems.newFileSystem(zipUri, env)) {
        // Create internal path in the zipfs
        Path internalTargetPath = zipfs.getPath(internalPath);
        // Create parent directory
        Files.createDirectories(internalTargetPath.getParent());
        // copy a file into the zip file
        Files.copy(toBeAdded, internalTargetPath, StandardCopyOption.REPLACE_EXISTING);
    }
}

public static void main(String[] args) throws Throwable {
    Path zipLocation = FileSystems.getDefault().getPath("a.zip").toAbsolutePath();
    Path toBeAdded = FileSystems.getDefault().getPath("a.txt").toAbsolutePath();
    createZip(zipLocation, toBeAdded, "aa/aa.txt");
}